Portal:Weather
The Weather portal
Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the lowest level of the atmosphere, the troposphere, just below the stratosphere. Weather refers to day-to-day temperature and precipitation activity, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth.
Weather is driven by air pressure, temperature and moisture differences between one place and another. These differences can occur due to the sun's angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations: the Hadley Cell, the Ferrel Cell, the Polar Cell, and the jet stream. Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow. Because the Earth's axis is tilted relative to its orbital plane, sunlight is incident at different angles at different times of the year. On Earth's surface, temperatures usually range ±40 °C (−40 °F to 100 °F) annually. Over thousands of years, changes in Earth's orbit can affect the amount and distribution of solar energy received by the Earth, thus influencing long-term climate and global climate change.
Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes, as most atmospheric heating is due to contact with the Earth's surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. The Earth's weather system is a chaotic system; as a result, small changes to one part of the system can grow to have large effects on the system as a whole. Human attempts to control the weather have occurred throughout history, and there is evidence that human activities such as agriculture and industry have modified weather patterns.
Studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiter's Great Red Spot, is an anticyclonic storm known to have existed for at least 300 years. However, weather is not limited to planetary bodies. A star's corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind.
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This dust storm occurred around Spearman, Texas on April 14, 1935. This was in the heart of the Dust Bowl, a period of severe dust storms and drought, which contributed to the Great Depression in the United States.
Recently selected pictures: Cordell, Oklahoma tornado, Mammatus clouds, Von Kármán vortex street, More...
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Recently selected articles: 1933 Atlantic hurricane season, Jet stream, More...
Did you know...
...that Hurricane Debbie is the only known tropical cyclone ever to strike Ireland?
...that the Tempest Prognosticator, one of the earliest attempts at a weather prediction device, employed live leeches in its operation?
...that eyewall replacement cycles are among the biggest challenges in forecasting tropical cyclone intensity?
...that the Braer Storm of January 1993 is likely the strongest extratropical cyclone ever recorded in the north Atlantic Ocean?
...that in medieval lore, Tempestarii are magicians with the power to control the weather?
...that the omega equation is essential to numerical weather prediction?
Recent and ongoing weather
- Wikinews weather portal
- August 10: New South Wales, Australia government says entire state in winter 2018 drought
- March 22: Sydney experiences hottest March day in 35 years
- March 7: Winter storm fells US President George Washington's tree at Mount Vernon estate, Virginia
- January 11: United States: At least fifteen dead in Southern California after rain causes mudslides and floods
- November 6: U.S. government report says climate change is human-made
- 2018 Atlantic hurricane season
- 2018 Pacific typhoon season
- Tornadoes of 2018
This week in weather history...
November 15: Start of the South-West Indian Ocean cyclone season
1989: Dozens were killed in a severe weather outbreak across the eastern half of North America, mainly in the Southeastern and Northeastern United States.
2006: Hurricane Sergio, the strongest Pacific hurricane on record in the month of November, reached its peak intensity, with maximum sustained winds of 110 miles per hour (180 km/h).
November 16
2007: Cyclone Guba reached peak intensity over the Coral Sea. Flooding from the storm's rainbands eventually killed more than 200 people in Papua New Guinea.
November 17
1999: Hurricane Lenny made landfall on Saint Croix. It was an unusual storm in many ways, striking the island as the strongest Atlantic hurricane on record for the month of November, while moving in an unprecedented west-to-east direction through the Caribbean.
November 18
2014: A major cold snap through much of the US reached its peak, with some temperatures reaching 45 degrees below normal.
November 19
1912: Robert Simpson, former director of the National Hurricane Center and co-inventor of the Saffir–Simpson scale of hurricane intensity, was born in Corpus Christi, Texas.
November 20
1996: Hurricane Marco, the longest-lived tropical cyclone ever recorded in the Atlantic Ocean in November, reached its peak intensity while meandering over the Caribbean Sea.
2007: Cyclone Guba reached peak intensity as it drifted near Papua New Guinea, causing flooding which would kill over 100 people.
November 21
2006: A nor'easter gave parts of Georgia and South Carolina their earliest snowfalls on record.
Selected biography
Vilhelm Friman Koren Bjerknes (March 14, 1862 – April 9, 1951) was a Norwegian physicist and meteorologist who did much to found the modern practice of weather forecasting. In 1895, he became professor of applied mechanics and mathematical physics at the University of Stockholm where he elucidated the fundamental interaction between fluid dynamics and thermodynamics. His major contribution was the primitive equations which are used in climate models. His son, Jacob Bjerknes, would introduce the ideas of weather fronts and the life cycle of extratropical cyclones, some of the most important advances in the history of meteorology.
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Categories
Weather: Meteorology | Atmosphere | Climate | Clouds | Cyclones | Floods | Meteorological concepts | Meteorological phenomena | Precipitation | Seasons | Severe weather and convection | Snow | Storms | Tornadoes | Tropical cyclones | Weather events | Weather lore | Weather hazards | Weather modification | Weather prediction | Weather warnings and advisories| Winds
Wikiprojects
WikiProject Meteorology is a collaborative effort by dozens of Wikipedians to improve the quality of meteorology- and weather-related articles. If you would like to help, visit the project talk page, and see what needs doing.
WikiProject Severe weather is a similar project specific to articles about severe weather. Their talk page is located here.
WikiProject Tropical cyclones is a daughter project of WikiProject meteorology. The dozens of semi-active members and several full-time members focus on improving Wikipdia's coverage of tropical cyclones.
WikiProject Non-tropical storms is a collaborative project to improve articles related to winter storms, wind storms, and extratropical weather.
Wikipedia is a fully collaborative effort by volunteers. So if you see something you think you can improve, be bold and get to editing! We appreciate any help you can provide!
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